Laminated glass



UNITED STATES PATENT OFFICE LAMINATED GLASS Walter Bauer and Paul mm...Danmtadt, Germany, assignors to Riihm a Haas Company,

Philadelphia, Pa.

No Drawing. Application February 20, 1034, Be-

rlal No. 712,170. 1933 This invention relates to the manufacture ofnon-shatterable glass, particularly that in which polymers of compoundscontaining the vinyl group are used as the intermediate layer. Such 5materials have been used in the past for this purpose, but we have nowfound that the addition of cellulose esters to this material in amountsup to 20% of the weight of the polymerized-material is very beneficial.Films of this material, when used as intermediate layers in laminatedglass, yield products which are very resistant to blows and shocks overa wide range of temperature and are particularly good in this respect atlow temperatures.

Among the materials which may be polymerized to yield the productsuitable for the manufacture of laminated glass according to the presentinvention are acrylic and methacrylic acids, their methyl, ethyl,propyl, butyl, .amyl, phenyl and benzyl esters; the chlorides, nitrilesand amids of these acids, and the vinyl esters such as the bromide,chloride, acetate, propionate, butyrate and benzoate. These compoundsmay beused alone or in a mixture of two or more. In the latter case, thejoint polymer of the monomeric substances yields very good material foran intermediate layer in laminated glass when used with cellulose estersaccording to the present invention.

Any of the ordinary esters of cellulose or mixtures thereof maybe used.These include the acetate, propionate, nitrate, and the mixed esterssuch as the nitrate-acetate, acetate-propionate or the acetate-butyrate,which can be mixed with a polymerized derivative of acrylic andmethacrylic acid to give clear, transparent films. In general thecellulose esters which give best results are those whose viscosity in10% solution in ethyl acetate or acetone is greater than 3 Engler, whenmeasured at 20 C. It is also ad-' vantageous when cellulose nitrate isused to add a stabilizer. For this purpose small amounts of urea,guanidln and its derivatives, phthalamid phenanthren, formaldehyde andzinc oxide may be added. When desired plasticizers such as the esters ofphthalic, phosphoric, tartaric, adipic, stearic and citric acids,acetins, diphenylene oxide, etc., may be added. Likewise artificial andnatural resins such as the copals, rosin, dammar, shellac, the aldehydecondensation products of p-toluenesulphonamid, phenol, urea, etc., aswell as the condensation products of polybasic acids with polyhydricalcohols. Mineral oils, vegetable oils, such as linseed, soya bean,China-wood, etc., and dyestuffs may also be added to get any desiredresult.

In Germanrl 'ebruary 21,

20 Claims. (01. 40-81) The amount of plasticizer used depends upon thecharacter of the polymerized material, .a greater amount being requiredwhen the polymerized material is brittle. Flor instance, whenpolymerized ethyl acrylate is mixed with 5% of cellulose nitrate, onlyabout 5% of plasticizer is necessary, whereas when polymerized ethylmethacrylate and 5% of cellulose nitrate are mixed, 30to 40% ofplasticizer will be required. The cellulose ester, plasticizer, etc.,can be added to the polymerized material before, during or afterpolymerization.

J illustration and are not intended to limit the invention in any way asto thematerials used or their proportions, or to the method making thelaminated glass. The figures for viscosity used in the examples and inthe appended claims refer to degrees Engler tor a 10% solution of thematerial in ethyl acetate at 20 C. The parts are by weight.

Example 1.--To a 25% solution of 70 parts of polymerized methylacrylate, (viscosity 20-25),

in ethyl acetate are added five parts of cellulose nitrate (viscosity340), ten parts of di-methyl glycolphthalate and fifteen parts ofdibutylphthalate. This solution is poured on a glass plate and thesolvent evaporated, leaving a film 0.5 mm. thick. The glass with thedried film is placed in a bath oi dibutylphthalate. A second glass sheetis placed in contact with the film, side of the first one and the twoare then pressed together at 70 C. and 10 atmospheres. A nonshatterableglass of improved quality is thus obtained.

Example 2.--To a 25% solution of 85 parts of polymerized -ethyl acrylate(viscosity 10), in ethyl acetate are added 10 parts of cellulose nitrate(viscosity 340), parts of diisobutylphthalate and 0.05 part ofdiphenyldiethylurea. A film 0.55 mm. thick is prepared from thissolution and placed between two sheets oi glass in a bath ofcyclohexanol. The sheets of glass and film are pressed together at 60 to70 C. A nonshatterable glass having improved resistance to shock betweenand +50 C. is obtained.

Example 3.-80 parts 01 a polymerized substance obtained by the jointpolymerization 01 equal parts of methyl aerylate and ethyl acrylate andhaving a viscosity oi 15 to 20, are made up in an 18% solution to whichare added five parts of cellulose nitrate (viscosity 2500' Engler), 10parts or diisobutylphthalate, 5 parts oidiethylglycolphthalate and 0.05part of urea. This solution is poured on two glass sheets and thesolvent evaporated, leaving a film 0.25 mm. thick on each. The sheetsare then placed together with the film sides in contact and pressed atabout 70' C. and i5 atmospheres. A non-shatterable glass is obtainedwhich is particularly resistant to shock and blow at low temperatures.

Example 4.-55 parts of polymerized ethyl methacrylate (viscosity 30 to40) is made up to a 20% solution in ethyl acetate. To this solution areadded 2.75 parts of cellulose nitrate (viscosity 250), 40 parts ofdimethylglycolphthalate and 0.25 part 01' phenanthren. A film 0.6 mm.thick is made from this solution and pressed between two glass sheetsand an improved nonshatteraple glass is obtained.

Example 5.82 parts oi polymerized ethyl acrylate are made up to a 20 tosolution and to this solution are added 5 parts oi cellulose nitrate(viscosity 340), 5 parts of cellulose acetate-propionate (viscosity34.3), 8 parts of di amylphthalate and 0.05 part of phthalamid. Thesolution is poured on a glass sheet and after evaporation of the solventa film 0.5 mm. thick remains. This glass sheet is placed in a bath ofeyelohexanol, and a second glass sheet placed in contact with the filmside. The two are then pressed together at 80' C. and an improvednonshatterable glass is obtained.

Example 6.-A joint polymer oi. 3 parts oi.

methyl acrylate and 1 part of acrylic nitrile is.

prepared. 70 parts 01 this Joint polymer are made up in acetone to a 20%solution and to this solution are added five parts of cellulose nitrateand parts of dibutyl tartrate. A film 0.6 mm. thick is prepared andpressed between two glass sheets in the usual manner. A nonshatterableglass having improved resistance to shock and blow is thus obtained.

Ezample'7.-60 parts of polymerized vinyl acetate (viscosity 40') aremade up to a 20% solution in ethyl acetate and to this solution areadded 5 parts of cellulose acetate-propionate, parts ofdiethylglycolphthalate and 0.1 part at acrylic amid. This solution ispoured on a glass sheet and alter evaporation oi the solvent a film of0.8 mm. thick remains. This glass sheet is united with a second glasssheet by means of the film by pressing at elevated temperatures and animproved non-shatterable glass is thus obtained.

Example 8.To a 20% solution in methyl acetate of '2 parts oi polymerizedmethyl acrylate,'

which was polymerized in the presence of 5 parts of cellulose nitrateand 2 parts 01' cellulose acetate, are added 15 parts ofdibutylphthalate, 5 parts 01 dimethy llycolphthalate and 0.001 part 01'sine oxide, and the resulting solution is poured on a glass sheet. onevaporation of the solvent, a film 0.4 mm. thick remains. A second glasssheet is united with the film side oi the first one in a bath ofeyclohexanol and the two sheets are pressed together at about '70 C. Animproved non-shatterable glass is obtained.

Example 9.65 parts of the joint polymer of equal parts 01' methylacrylate, ethyl aerylate, ethyl methacrylate and acrylic nitrile aremade up to a 20% solution in acetone with 5 parts of cellulose nitrate,25 parts 0! dibutylphosphate, 10 parts of cyclohexyladipate and 2 partsof diphenlyene oxide. The solution is poured on a glass plate and thesolvent evaporated. A second glass sheet is united with the film side ofthe first one by pressing at elevated temperature, and an improvednon-shatterable glass is obtained.

Example 10.65 parts of polymerized isoan ylmethacrylate are made up to a25% solution in ethylacetate with 5 parts of celluloseacetatepropionate, 30 parts 01 dibutyl tartrate and 1 part ofp-toluenesulphonamid-iormaldehyde resin, and a film 0.6 mm. thick isprepared from this solution. The film is placed in a. bath ofdiethyleneglycolethyl ether between two glass sheets and these are thepressed together at elevated temperature. A non-shatterable glass soobtained is resistant to shock and blow over a wide range oftemperature.

Example 11.--95 parts of a joint polymer 01' equal parts of methylacrylate and ethyl acrylate are made up in solution with 5 parts of highviscosity cellulose nitrate and one part of di-ethyldiphenyl urea. Thissolution was poured on a glass sheet and after drying was placed in abath of diisobutylphthalate and a second glass sheet placed in contactwith the film side. The whole was then pressed at elevated temperatureand a very resistant non-shatterable glass obtained.

This invention is not limited by the above examples. Any oi the ordinarysolvents in which both the polymerized material and the cellulose esterare soluble may be used, as for example,

chloroform, ethylene dichloride, amyl acetate,

butyl acetate, or mixtures of these solvents with each other or withdiluents which will not cause a precipitation of any of the components.

The process of polymerization may also be carried out in any desiredway, for instance in the presence of suitable accelerators such asorganic and inorganic peroxides or in the presence of light, heat orpressure.

In making the laminated glass, any suitable process may be used. Thesolution of the combined materials may be spread on one or both oftwoglass sheets and after evaporation of the solvent, may be pressedtogether, or the dry film oi' the laminating material may be preparedseparately and then pressed between two glass sheets.

In making the laminated glass from the dry film, an adhesive may be usedii desired. This I adhesive may be made from the same or similarmaterial as the dry film, or from any other suitable substance. Likewisethe glass or the film or both may be moistened with a suitableplasticizer to asaist'in securing complete contact and the properinitial adhesion between the glass and the laminating material. Thecellulose ester may be used in any amount up to 20% by weight of thepolymerized material. This amount will vary with the desired results andwill depend somewhat on the properties oi the particular polymer orjoint polymer with which it is used. With any given polymerizedmaterial, larger amounts-o! the cellulose will tend to yield a filmmaterial which is harder and stifler than that obtained from thepolymerized material alone. The hardness of the laminating material willbe determined largely by the use for which it is intended. This may bevaried to suit any possible conditions by adding various amounts ofplasticizer or by a suitable choice of the polymerized material.

What we claim is:-

1. Anon-shatterable laminated'giass comprisa polymer of vinyl acetateand a, cellulose ester ing a plurality of sheets 01' glass and as theinterposed strengthening layer a material; comprising a polymer of atleast one ester containing a vinyl group, and a cellulose ester in anamount not over 20% of the polymerized material.

2. A non-shatterable laminated glass comprising a plurality of sheets ofglass and as the interposed strengthening layer a material, comprising apolymer of at least one ester containing a vinyl group, and a celluloseester whose viscosity in 10% solution in ethyl-acetate is at 20 C.greater than 3 Engler in an amount'not over 20% of the polymerizedmaterial.

3. A non-shatterable laminated glass comprising a plurality of sheets ofglass and as the interposed strengthening layer a material, comprising apolymer of at least one ester containing a vinyl group, a celluloseester in an amount not-over 20% of the polymerized material, and aplasticizer. i

4. A non-shatterable laminated glasscomprising a plurality. of sheets ofglass and as the interposed strengthening layer a material, comprisingthe.;loint polymer ofat least two polymerizable esters containing thevinyl group, and a cellulose ester, in amount not over 20% of the jointpolymer.

5. A non-shatterable laminated glass comprising a plurality of sheets ofglass and as theinterposed strengthening layer a'material comprising thejoint polymer of at least two polymerizable esters containing the vinylgroup, a cellulose ester in amount not over 20% of the joint polymer,and a plasticizer.

6. A non-shatterable laminated glass comprising a plurality of sheets ofglass and as the interposed strengthening layer a material comprising atleast one polymerized ester of the group consisting of acrylic acid andmethacrylic acid, and a cellulose ester in amount not over 20% of thweight of the polymerized ester.

7, A non-shatterable laminated glass comprising a plurality of sheets ofglass-and as the interposed strengthening layer a material comprisingthe joint, polymer of at least one polymerizable ester containing thevinyl group and at least one polymerizable compound of the groupconsisting of the amids andnitriles of acrylic and methacrylic acids,and a cellulose ester in amount not over 20% of the weight of the jointpolymer.

8. A non-shatterable laminated glass comprising a plurality of sheets ofglass and as the interposed strengthening layer a material, comprising apolymer of methyl acrylate, and cellulose nitrate, the cellulose nitratebeing present in amount not over 20% ot the weight of the polymerizedmethyl acrylate.

9. A non-shatterable laminated glass comprising a plurality of sheets ofglass and as the interposed strengthening layer a material comprisingthe polymer of vinyl acetate and a cellulose ester in amount ,notexceeding 20% of the weight of the vinyl acetate.

10. A non-shatterable laminated glass comprising a plurality of sheetsof glass and as the inter-. posed strengthening layer a material,comprising a polymer of methyl acrylate and cellulose nitrate, thecellulose nitrate being present in amount not over 20% ot the weight ofthe polymerized methyl acrylate, and a plasticizer.

11. A non-shatterable laminated glass comprising a plurality of sheetsof glass and as the interposed strengthening layer a material,comprising in amount not exceeding 20% of the weightof the vinylacetate, and a plasticizer.

12. A non-shatterable laminated glass comprising a plurality of sheetsof glass and as the inter-' posed strengthening layer a material,comprising a joint polymer of an ester of acrylic acid and an ester ofmethacrylic acid, and a cellulose ester, the cellulose ester beingpresent in amount not over 20% of the joint polymer.

13. A material suitable for the reinforcing layer in non-shatterableglass comprising the joint polymer of at least one polymerizable estercontaining the vinyl group and at least one polymerizable compound ofthe group consisting of the amldsand nitriles of acrylic and methacrylicacids, and a cellulose ester in amount not exceeding 20% of the weightof the polymerized material.

14. A material suitable for the reinforcing layer in non-shatterableglass comprising a polymer of an ester ofthe group consisting of acrylicand methacrylic acids, and a cellulose ester, the cellulose ester beingpresent in amount not over 20% of the weight of the polymerizedmaterial.

15. A material suitable for the reinforcing layer in non-shatterableglass comprising a joint polymer of at least one ester of acrylic acidand at ,leastpneester of methacrylic acid, and a cellulose ester,thecellulose ester being present in amount not exceeding 20% of thejoint polymer.

the presence of the said organic cellulose deriv-- ative.

18. As a new article of manufacture, a sheet of laminated safety glasscomprising two sheets of glass and an interposed'layer of plasticmaterial formed from a mixture of an organic cellulose derivative and apolymerized ester of an unsaturated organic compound made lay-dissolvingor dispersing the cellulose derivative in the unpolymerized ester ofthe. unsaturated compound and then polymerizing the ester in thepresence of the organic cellulose derivative so-- lution or mixture. ri,

19. As a new article of manufacture, a sheet of laminated safety glasscomprising two sheets of glass and an interposed layer of plasticmaterial formed from a plasticizer mixture of an organic cellulosederivative'and a polymerized ester of an unsaturated organic compoundpolymerized in the presence of the said organic cellulose derivative.

20. A laminated plate consisting of a pair of glass sheets with aninterposed reinforcing layer of an organic cellulose derivatiyeincluding one of the lower aliphatic esters of acrylic acid whichderivative in solution.

WALTER BAUER. PAUL WEISERT.

